The present disclosure relates generally to rotary machines, and, more specifically, to methods and systems for use in providing sealing between components within gas turbine engines.
At least some known rotary machines, such as gas turbines, include a plurality of seal assemblies in a fluid flow path to facilitate increasing the operating efficiency of the gas turbine. For example, some known seal assemblies are coupled between a stationary component and a rotary component to provide sealing between a high-pressure area and a low-pressure area. In addition, at least some known gas turbines include at least one stator vane assembly and at least one rotor blade assembly that collectively form a stage within the gas turbine. In at least some known gas turbines, seals are provided between static components in adjacent stages, or between components within a stage. However, such seals are located relatively remotely, in a radial direction, from an axis of rotation of the gas turbine. In at least some known gas turbines, there are components that are exposed to a flow of hot combustion gases, and that are fabricated from materials configured to withstand exposure to high temperatures. Moreover, in at least some known gas turbines, there are other components that, in ordinary operation of the gas turbine, are not directly exposed to hot combustion gases and are not fabricated from high temperature-resistant materials. To protect such areas of the gas turbine that are not high-temperature-resistant, sealing structures are provided to define a pressure boundary between high-temperature and lower-temperature areas. A cooling fluid (typically air) is supplied into the low-temperature, higher-pressure areas of the gas turbine on a side of the sealing structures opposite the lower-pressure hot combustion gas path. This cooling fluid (also sometimes referred to as purge air) is used to help prevent ingestion of combustion gases into the low-temperature areas of the gas turbine. The use of excessive amounts of purge air may result in a lowering of efficiency of the gas turbine.